Studies were carried out in human fibroblasts grown in culture on the effects of hormonal factors on sterol synthesis and cellular cholesterol content and on the stimulation of cholesterol synthesis by digitonin and by salts of Fe and Mn. The changes in subcellular pools of free and esterified cholesterol under the influence of environmental factors are being investigated. BIBLIOGRPHIC REFERENCES: Avigan, J.: Cultured human fibroblasts in the study of atherosclerosis. In Atherosclerosis: Metabolic Morphologic and Clinical Aspects. Adv. Exper. Med. Biol. 82, p 724, Plenum Press, New York, 1977. Avigan, J.: Studies on the effects of hormones on cholesterol synthesis in mammalian cells in culture. In Cholesterol Metabolism and Lipolytic Enzymes, J. Polonovski, Ed., Masson Publ. U.S.A. Inc., New York, 1977, pp 1-12.